I have 1978 140hp Chrysler, and I'm trying to add a tach, but I'm not sure how to tell how many poles my alternator has.<br /><br />From the TeleFlex website:<br />"Almost all outboard engines that have an alternator can be monitored by our Universal Outboard Tachometer. That is because most outboard alternators have magnetic pole ranges from 4 to 12 poles. The tachometer is adjustable to those ranges. However, some late model Chrysler outboards and most pre 1993 Force outboards have Prestolite 20 pole alternators. The Universal tachometer is not adjustable for that number of magnetic poles. To expand the existing Universal tachometer from 4 to 20 pole would jeopardize the electronic noise filtering. Therefore, a tachometer that handles only the 20-pole alternator was created. The Teleflex catalog and brochures specify this tachometer, P/N 53743P.Most Force engines built after 1992 have more standard 12 pole alternators and can be monitored by the Universal Outboard Tachometer."
